﻿/* Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
namespace Sys.Workflow.Engine.Cfg
{
    using Sys.Workflow.Engine.Impl.Cfg;

    /// <summary>
    /// Implementations of this class can be plugged into a <seealso cref="ProcessEngineConfigurationImpl"/>. Such implementations can configure the engine in any way programmatically possible.
    /// 
    /// 
    /// </summary>
    public interface IProcessEngineConfigurator
    {

        /// <summary>
        /// Called <b>before</b> any initialisation has been done. This can for example be useful to change configuration settings before anything that uses those properties is created.
        /// 
        /// Allows to tweak the process engine by passing the <seealso cref="ProcessEngineConfigurationImpl"/> which allows tweaking it programmatically.
        /// 
        /// An example is the jdbc url. When a <seealso cref="IProcessEngineConfigurator"/> instance wants to change it, it needs to do it in this method, or otherwise the datasource would already have been created
        /// with the 'old' value for the jdbc url.
        /// </summary>
        void BeforeInit(ProcessEngineConfigurationImpl processEngineConfiguration);

        /// <summary>
        /// Called when the engine boots up, before it is usable, but after the initialisation of internal objects is done.
        /// 
        /// Allows to tweak the process engine by passing the <seealso cref="ProcessEngineConfigurationImpl"/> which allows tweaking it programmatically.
        /// 
        /// An example is the ldap user/group manager, which is an addition to the engine. No default properties need to be overridden for this (otherwise the
        /// <seealso cref="#beforeInit(ProcessEngineConfigurationImpl)"/> method should be used) so the logic contained in this method is executed after initialisation of the default objects.
        /// 
        /// Probably a better name would be 'afterInit' (cfr <seealso cref="#beforeInit(ProcessEngineConfigurationImpl)"/>), but not possible due to backwards compatibility.
        /// </summary>
        void Configure(ProcessEngineConfigurationImpl processEngineConfiguration);

        /// <summary>
        /// When the <seealso cref="IProcessEngineConfigurator"/> instances are used, they are first ordered by this priority number (lowest to highest). If you have dependencies between
        /// <seealso cref="IProcessEngineConfigurator"/> instances, use the priorities accordingly to order them as needed.
        /// </summary>
        int Priority { get; }
    }
}